Field of the Invention
The present invention relates to a polypeptide having proline-specific endoprotease activity, a composition comprising the polypeptide, a nucleic acid encoding a proline-specific endoprotease, an expression vector comprising the nucleic acid encoding a proline-specific endoprotease, a recombinant host cell, a method for preparing proline-specific endoprotease and a process for preparing a food or feed product wherein the proline-specific endoprotease is used.
Description of Related Art
Proline-specific endoproteases are enzymes that hydrolyse a protein or peptide at a position where there is a proline in the protein or peptide.
A proline-specific endoprotease may for instance be derived from Aspergillus niger or Penicillium chrysogenum, such as disclosed in WO2002/046381 and WO2009/144269 respectively.
Other proline-specific endoprotease are known from WO2012/174127. WO2012/174127 discloses proline-specific protease from Botryotini fuckeliana, Aspergillus clavatus, Sclerotinia sclerotiotum, Mycosphaerelly graminicola, Neuropspora crasse, Talaromyces stipitatus and Gibberella zeae. 
Proline-specific endoprotease can be used in several applications, for instance in the degradation of gluten (see for instance WO2005/027953 or WO2003/068170). Gluten is the insoluble protein fraction of cereals like wheat, rye, oat and barley. Gluten is a complex mixture of glutenin- and prolamine molecules which are thought to cause toxic effects, for instance in patients suffering from celiac disease. Celiac Sprue or celiac disease is considered to be an autoimmune disease. Patients suffering from Celiac Sprue need to follow a strict gluten-free diet, which is very difficult to follow because gluten is so widely used. The use of proline-specific endoprotease as a medicament or dietary supplement may alleviate the need for a strict gluten free diet (WO2003/068170).
Proline-specific endoproteases are also used for reducing haze in beer, wherein the proline-specific protease may be added during several stages of a beer production process (WO 2002/046381).
It is desirable that enzymes in food and feed applications have a suitable pH optimum and preferably are not active in the final food or beverage.
The aim of the present invention is an alternative proline-specific endoprotease with improved characteristics.